Smoking causes one in 10 deaths worldwide, half of them in just four countries — China, India, the US and Russia, a new study revealed on Thursday.
The Global Burden of Diseases Report was based on smoking habits in 195 countries and territories between 1990 and 2015, the BBC reported.
It found that nearly one billion people smoked daily in 2015 — one in four men and one in 20 women.
Despite decades of tobacco control policies, population growth has seen an increased number of smokers, it warned.
Researchers said mortality could rise further as tobacco companies aggressively targeted new markets, especially in the developing world.
"Despite more than half a century of unequivocal evidence of the harmful effects of tobacco on health, today, one in every four men in the world is a daily smoker," said senior author Emmanuela Gakidou.
"Smoking remains the second largest risk factor for early death and disability, and so to further reduce its impact we must intensify tobacco control to further reduce smoking prevalence and attributable burden," the BBC quoted Gakidou as saying.
The number of tobacco-related deaths — more than 6.4 million in 2015 — increased by 4.7 per cent, the study showed.
Some countries have succeeded in efforts to help people quit, mostly through a combination of higher taxes, warnings on packages and education programmes.
Over the 25-year period, Brazil saw the percentage of daily smokers drop from 29 to 12 per cent among men and from 19 to 8 per cent among women.
But, the report said, Bangladesh, Indonesia and the Philippines saw no change from 1990 to 2015.
The report was published in the medical journal The Lancet.